TEGUCIGALPA, Honduras (AP) — A police operation to dismantle a drug trafficking cartel wasn’t as successful as it should have been because corrupt authorities alerted the traffickers weeks ahead of time, a Honduran official said Thursday.

Seized Property Administration Office director Humberto Palacios said officials seized 71 bank accounts from Los Cachiros drug gang during the September operation and that none of them had any funds and the houses and businesses seized were also empty.

“There weren’t any automobiles, machinery, or documentation on the assets,” Palacios said. “They left us nothing.”

Palacios said investigators learned that a tenant who rented one of the seized properties began looking for another house a month before police acted because he knew of the authorities’ plan.

U.S. and Honduran authorities say brothers Javier Eriberto Rivera and Devis Leonel Rivera are the leader of Los Cachiros, which works with Mexico’s Sinaloa Cartel and allegedly controls 90 percent of the nation’s clandestine landing strips.

The U.S. Treasury Department last month imposed financial sanctions against the two brothers, their parents, and two other siblings. According to the U.S. government the gang uses the proceeds from drugs in farming, mining and real estate companies. Five companies allegedly tied to the gang were also sanctioned.